Returning Algae

[mishawver]

Help for a new pool owner! Some background. We bought house with pool and moved in August 16th. I had a pool guy scheduled to give me a pool 101 lesson 5 days later. In the meantime, I did not add anything to the pool because wasn’t sure what to do. The most I did was use the test strips which showed that everything was in balance except for a tad high pH, according to the bottles label. I also noticed that the pump was running 24/7 and that the pressure gauge on the sand filter was broken. The previous owners had no chemicals on hand, their brush was dry rotted, they had a dolphin cleaner in the garage boxed up, and they did have a Polaris in the pool that was set to run for 4 hours a day. They did have a weekly pool maintenance service.
When we arrived the pool was very clear. I judge this by how well I can see drain in the deep in. Info on my pool is in footer of my post. I will comment that the plaster is wearing off as there are grey patches along the top and floor of shallow end. The grey areas are quite rough compared to the smooth plaster finish.
So I get the pool 101. He said pump should not have to run 24/7 so he set timer for pump to run 12 hours a day. He said Chlorine was low but not zero, so he put three tablets each of the 3” tabs into both skimmers. pH was high so he added muratic acid. He also demonstrated how to do a backwash. He suggested we try out the dolphin cleaner since it will sweep the sides of wall and floor whereas the Polaris only picks up debris but does not sweep. I may have misunderstood but I thought he said the dolphin would take the place of me having to sweep the sides with a brush. By this time, the water wasn’t as clear but he said not bad. His advice in general was to keep the chlorine and pH in check and I should be fine. He cautioned on pool stores trying to sell me stuff and if they start talking alkalinity and stabilizer adjustments and phosphates removal to not bite.
So for the next two weeks after pool 101, I’m testing the water, keeping a single tablet in each skimmer, emptying baskets of leaves, and running the dolphin and filter for 12 hours a day (I’m not manually sweeping). No backwashing because the returns looks strong as they did after the backwash demonstration. I started to notice the pool getting cloudier so I start researching. Then I noticed it was getting a greenish tint. I saw no actual algae. Took sample to pool store for first time. Balance was good except for phosphates at 500 ppm. They suggested I add phosphate removal. I balked until I could come and read on this and most said 500 ppm is not issue. So I did not add but did add clarifier and started filter online for 24/7 and backwashed. I also replaced the pressure gauge so I could check backpressure on filter. I think I was in denial that I would get algae after keeping everything in balance.
After about day, I noticed algae settling on the steps. I took my new brush and ran on walls. Whoa a green hazy cloud. So being jolted out of my denial, I did the shock treatment. I didn’t do the 4lb shock as one pool store suggested, I did the shock that would get me to above 10 ppm. I had read that somewhere and also another pool store. My chlorine was 5 ppm before shocking. The next day algae settled onto the floor and I vacuumed to waste. Still cloudy so I added clarifier again and backwashed filter. The next day, I could see the drain again very clearly. So that gets us closer to current time. We went swimming, pool was clear. I felt so successful.
So this past Sunday, I was going to be the good pool owner and sweep down the walls myself after learning my lesson. One swipe and looked like green tinted particles. I was “shocked”. I did this along all the walls and steps. Very similar green particles. Drain disappeared again after sweeping. Only a faint glimpse could be seen. Not completely gone as last time. since I had already shocked once, I lost my fear of shocking, and did again before it got the green tint. As suggested, I always sweep the sides and floor before shocking.
The next day, visible algae on the bottom but not as much as first time. I vacuumed to waste. The pool store (although I know don’t always listen) suggested to follow with algaecide. Since I was in a panic I did. It has been almost 24 hrs and no visible algae has settled, except for two fly size drops on pool steps. Pool is still a white cloudy. When I run the brush ( I have become obsessed with the brush), I still stir up stuff. I can’t tell if green tint or whitish but my mind tells me green.
So I’m not sure if I am just chasing my tail by shocking, vacuuming, clarifying, sweeping walls, backwashing…to clear up…and then start all over.
In the meantime, I got tired of the all over the place pool store results so I bought a test kit. I’m still not happy with how to measure chlorine. It is till color based and can only go to 10 ppm. Below are results from sample I took to store today. In parenthesis is my results based on test kit.

Free Cl : >= 12 ppm (>= 10 ppm)…max on test limits
Total Cl: same as Free Cl
pH: 7.3 (7.5)
Hardness: 200 ppm (1500 ppm….I must have done something wrong)
Corrected Alkalinity : 37 ppm (37 ppm)
CyA: 61 ppm (70 ppm)
Copper: 0.01 ppm (did not measure)
TDS: 250 ppm (did not measure)
Phosphates: 0 ppm (hmm…where did they go from previous sample)

My TA has always been low but no pool place ( I have tried three) has suggested increasing. My understanding is that it helps against pH upsets. My pH stays steady.
Pool stores always say water is fine. When I tell them cloudy and green film when brushing walls, then that is where they all have different approaches. The latest was to use bromine. Another was to use copper algaecide (that one doesn’t sound good).

The previous owners have been difficult to get info from. I don’t know age of sand and if filter on 24/7 because poor filtering efficiency. I’m not sure who the pool maintenance service was. I would like to contact them to see if they had problems and if they did weekly shocks or algaecides as some sites suggest to do. I like to think if I keep chemistry balance, sides swept, leaves out, skimmers clean, I should not need that. I’m also wondering if the plaster wearing off is giving places for algae to grab onto.
So suggestions on what my problem may be. And also, are there test kits where I can measure an actual value of chlorine versus the color strips or the color drops.
Sorry so lengthy. Wanted to explain how I got to this point in my short pool ownership.

 

[jblizzle]

Welcome to TFP!!!

I will admit I did not read the first half in much detail and my comments are all over the place. But, if sounds like you have made a good decision to take control for yourself and stop listening to the pool stores.

What test kit did you get? Note that the Recommended Test Kits include the all important FAS-DPD chlorine test which is NOT a color matching test and it will accurately read much higher FC and CC levels. It looks like you may just need to add the FAS-DPD to your kit and then you will have the equivalent.

You will learn a lot by reading Pool School and asking questions here ... very quickly you will know more than the pool store employees.

Based on your numbers (ignoring the CH which seems off), your CYA is already higher than we would recommend (30-50ppm). This number is critical as it determines what level you need to maintain for the FC. See: FC/CYA Chart

Ignore phosphates, nitrates, etc. Do NOT add any copper. There is rarely ever a need for algeacides, clarifiers, etc. Sand rarely needs to be replaced, but cleaning can be a good idea.

Since you see algae, you need to SLAM the pool. [slam:2uqqu324][/slam:2uqqu324] To do this correctly you need the FAS-DPD test, and likely should replace about 30-40% of your water to get the CYA level down before you start.

Please ask questions since I just threw a bunch of random info at you and I am not exactly sure what specific questions you were asking ... but hopefully all my :blah: will trigger learning and questions.

 

[mishawver]

Thanks for comments. If we are planning to replaster pool next season, should I just maintain a higher chlorine level vs draining and refilling half of pool. And what should I use for chlorine instead of tablets that have stabilizer in them. I think about half is stabilizer. If I could eliminate that new stabilizer then current levels should dilute over time with rain or refilling after I vacuum to waste.

 

[zea3]

Hi, welcome to TFP! You will have a few decisions to make in order to clear your pool. The first and most important decision is to pick one source of advice and follow it and it only. Of course we believe we offer the best advice and we can back it up with thousands of members who have been in your shoes, and our advice will be less expensive than either the pool service or the pool store recommendations. Here are my comments on what you have done so far:

1. Clarifier does not kill algae. All clarifier does is cause debris to settle at the bottom of the pool to make it easier to vacuum it out. It is not necessary for most pool owners.

2. Getting your own test kit was a good idea, however you need a FAS/DPD chlorine test to be able to test FC levels greater than 10 ppm. You can order just that test from TF Testkits and add it to the test kit you purchased. This test is essential for clearing your pool. (I will explain why later.)

3. Stop using chlorine tablets and any other form of dry chlorine you have been using. Your CYA is too high for a manually chlorinated pool, and dichlor/trichlor products all add CYA to the pool. The only way to lower the CYA is to drain and replace some of the water. Use the Pool calculator to determine how much to drain to lower the CYA to 20-30 ppm for the slam process.

4. Do not use any algaecide, especially copper based algaecide. They are not effective at killing algae and are designed to help prevent algae in the first place. The best product to kill algae is liquid chlorine and lots of it. Algae will not grow in a properly chlorinated pool.

5. Don't worry about the TA. Its main function is to stabilize pH. If your pH is stable then don't worry about it.

6. Don't worry about the age of the sand in the filter. All sand is pretty old if you think about it. The filter may need to be deep cleaned to flush out debris and re-settle the sand bed. This is a practice that should be done every few years. We can discuss how to clean the sand at a later time.

What you need to do to clear the pool is the following:

1. Read through Pool School and focus on pool water chemistry and the slam process.

2. Order the FAS/DPD Chlorine test. You will not find this test in pool stores.

3. Stock up on liquid chlorine. Compare prices to see if the higher concentrated liquid chlorine from the pool store is a better value than plain, unscented bleach from your grocery store.

4. Use the Pool calculatorto determine how much water you need to drain to lower the CYA to around 20-30 ppm. You will use less chlorine while completing the slam process if you lower the CYA.

5. Continue brushing the pool, daily if possible and keep the filter going 24/7 during the slam process.

We can help you take control of your pool if you follow our advice. Read through a few of the threads that our members have posted about their experiences fighting algae.
my success story before and after pics
my TFP success story
success story algae cloudy pool

Feel free to ask questions anytime!

Can you post pictures of the pool, especially the plaster damage? We may have some thoughts on that as well.

 

[jblizzle]

You are correct the CYA should slowly drop due to backwashing, splash out and rain dillution. 70ppm is really not WAY too high, so it would be doable to wait.

According to the chart, you should never let you FC get below 5ppm and when you SLAM you need to maintain the FC at 28ppm.

For the chlorine source, you need to use liquid chlorine which is just plain old bleach (no scents, outdoor, thicker, etc)

 

[mishawver]

Great suggestions. I have read pool school and forums but there is so much info that its overwhelming. However I think I have a good basic understanding but needed that nudge. You have filled in some gaps and given a focused place to look.
I had to chuckle at the age of sand comment.
As for pics. I just took some. Need to figure out how to post

 

[mishawver]

Here are couple of picture if plaster

 

[mishawver]

Hope pictures show where plaster has worn off. Excuse bad grammar. In previous post. iPhone typing is not my strong point. Here is another picture where pool starts to deepen.

 

[Jeetyet]

I don't know anything about plaster pools, but just looking at your pics they remind me of some I've seen of metal staining. I notice you stated those areas were rougher than surrounding areas so that may not be the case here, but, if you have some vitamin C tablets it would be easy enough to test. In case you havn't ran across posts about that yet, basicly all you do is drop a vitamin C tablet in one of the affected areas and let it sit a bit and see what happens. IF its a metal stain the area around the tablet should lighten very quickly.

 

[zea3]

Its hard to tell but the darkened areas of plaster could be calcium scale. There would be some sort of shallow depression or crater in the darkened areas if the plaster was gone. If there is not, try to scrape a little bit of it off and put a couple of drops of muriatic acid on it. If it bubbles up it is probably calcium scale.

 

[Jeetyet]

One other thing I'd like to point out. You mention that you've been putting pucks in the skimmers. Not a good idea, especially if the pump isn't on 24/7 until they've completely dissolved.

As already pointed out you should stop using them anyway, but, sometimes they can come in handy if you're going to be away from the pool for a while. I'd suggest for those times that you get a floater to put them in instead of the skimmer basket.

 

[mishawver]

Okay I have ordered the test kit to supplement the one I already had. I have also read the SLAM process. Here are some followup questions:

1. I've checked local pool stores and they said liquid chlorine is not sold in this area. This was confirmed by a pool guy that came out to show me how to operate equipment. So is bleach the only option now? Can the granual chlorine be used? If not, why? Does it take longer to dissolve and equalize in system or because of addtional CH

2. There are three things to check during SLAM to determine if process is complete. As of now, my water is clear. According to pool store, CC is zero (will check when I have my test). So only thing not checked is overnight chlorine test for which I can't do yet. If my water is still clear and CC is low once test kit is here, should I just do the overnight test with current levels? I'm confindent I did not get all the algae with my last shock even with clear water, so I'm sure once the test kit gets here, I can easily get water cloudy again by sweeping walls.

3. So how is clear defined. I define it by how well I can see the drain which is subjective and hard to measure differences. Any suggestions.

4. Backwash as needed during process. Do you recommend backwash when backpressure is 10 psi greater than clean pressure or when the pressure has increased 25% of clean presssure. That's about a 7 lb difference for me. I've seen both recommendations.

5. Is overbrushing a problem? I've been doing several times a day. And has anyone used the whale brush. Description says it helps keep brush against wall which I find difficult with my current brush.

6. How long does it typically take to mix the chlorine in pool once added. I'm not sure of my pump output so don't know turnover of pool. I think SLAM says not to make adjustments more frequently than an hour

7. What happens with the salts from the bleach? Do they get filtered eventually

8. I like the thought of filtering faster by adding DE. What can be the downside to this? New learning for me.

9. What levels will be safe to swim after the SLAM process is complete. If I have to target say 28 for current CYA levels, how low should I get it before letting kids swim. How long does it take to work off if there is no active algae to consume it quickly.

Followup on pictures: I tried to scrape but nothing came off. When I run the polaris or the dolphin, it sometimes picks up white flakey material. Could that be the coating. I finally spoke with the man who has serviced this pool for last 7 years. He said the pool was painted about 6 years ago and the dark spots are where the paint has come off? Pools are painted? Is that similar to the plaster coating.

Question: The former pool maintenance guy also told me that the owners added a mineral pack to the pool. There is a metering device downstream of pump. He said a mineral pack was placed in there. I have not heard of minerals added to pools. Can someone point me in right direction as to what this might be.

He also told me he added stabalizer at beginning of season and used non stabalized chlorine tabs. He was surprised when I told him that no one around here carries them. Is this something that is not common to use. I like the thought of a tablet so that when we are gone we can continue to add. I've seen some threads on that so I will investigate more. For the life of me, I don't understand why anyone uses stablaized tabs. Maybe in rainy states it makes sense.

Thanks for all the help. I really feel like I have made it to my next level of understanding.

 

[linen]

1. I've checked local pool stores and they said liquid chlorine is not sold in this area. This was confirmed by a pool guy that came out to show me how to operate equipment. So is bleach the only option now? Can the granual chlorine be used? If not, why? Does it take longer to dissolve and equalize in system or because of addtional CH

I highly doubt that, don't you have home depots or lowes around you? But bleach is fine too. Granular chlorine is either cal-hypo or dichlor. Dichlor adds cya, cal-hypo add calcium. See: http://www.troublefreepool.com/pool-school/types_chlorine_pool

2. Wait for your kit, test all levels and post.
3. Clear as in crystal.
4. When pressure goes up 25% from clean pressure.
5. Nope, brushing is good.
6. You can usually test within 1/2 hour, but it is good to wait an hour.
7. The salt level goes up which is not a problem.
8. Your filter will need backwashing much sooner, so if you can't be near the pool (during the SLAM process), don't use DE.
9. You can safely swim up to your SLAM level. Assuming you get sun on the pool, it will consume the FC over a couple of days.

Question: The former pool maintenance guy also told me that the owners added a mineral pack to the pool. There is a metering device downstream of pump. He said a mineral pack was placed in there. I have not heard of minerals added to pools. Can someone point me in right direction as to what this might be.

Don't use minerals/mineral packs, they add metals (typcially copper) to the pool which you do not need in a properly chlorinated pool. Copper can stain pool surfaces and turn blond hair green.

He also told me he added stabalizer at beginning of season and used non stabalized chlorine tabs. He was surprised when I told him that no one around here carries them. Is this something that is not common to use. I like the thought of a tablet so that when we are gone we can continue to add. I've seen some threads on that so I will investigate more. For the life of me, I don't understand why anyone uses stablaized tabs. Maybe in rainy states it makes sense.

Almost 100% of tabs available to buy contain cya (stabilazer), it is rare but there are some cal-hypo tabs. Note: Never put cal-hypo tabs in a trichlor tab feeder!

 

[linen]

Oh, I forgot to add...Welcome to tfp, mishawver

 

[jblizzle]

1. Yup. Stick with regular bleach ... all forms of solid chlorine have understandable side-effects. Some add stabilizer (CYA) others add calcium (CH) ... if either of those build up too high you will have issues. There is lithium chlorine, but it is very expensive.

2. Do you see algae anywhere? If so, you need to SLAM correctly. I would at least raise the FC up to near SLAM level and do the OCLT to confirm (if you do not see anything).

3. "Clear" means that you do not see algae anywhere in the water or the walls and can easily see the bottom ... you should be able to tell why types of screws are in the floor drain.

4. Clean the filter when the pressure rises 20-25% over the clean pressure. What is your clean pressure?

5. Brush as much as you can (or want). The wall whale is awesome.

6. Wait around an hour after adding the bleach with the pump on before you retest. You should also be running the pump for 30-60 minutes before you do any testing.

7. They will slowly build-up in the pool, but generally the levels remain well below what a SWG pool would have. No issue here.

8. Adding DE will require more frequent backwashing, but it can certainly be effective to clear up a cloudy pool ... once all the algae is dead.

9. It is safe to swim as soon as the FC is less than SLAM level ... and even at SLAM level the active chlorine in the water is likely less than half of what you would find in a public pool that does not use stabilizer.

Painting is not generally a good idea as it just does not last. Pictures did not look like paint to me, but hard to tell.

Mineral packs are what add metal to the water and that could lead to staining (which is kind of what the pool looks like to me). We do NOT recommend the use of any metals in the pool.

non-stabilized chlorine tabs are nearly non-existent. Some can be found that are cal-hypo and add calcium, but they generally fall apart. I think the pool guy did not know what he was talking about.

 

[mishawver]

Great advice. Can't wait to get my test kit.

I want to rush home now and yank the tabs out of water. I was waiting till I read up on the BBB method. I'm gonna be gone this weekend. How often do you test and adjust when not using tabs.

I was just at pool store seeing what they had. They just won't budge on 150 stabilizer is okay. H
That's there action limit. And when I told them that means more chlorine hey said no it doesn't. What data are they looking at ?

As for my clean pressure for filter asked above. 10 psig. I've back washed at 13 psig.

I can't make out screws on drain. So not crystal clear but can see drain now.

Thanks again. Gonna go read the BBB method

 

[jblizzle]

To start you should be testing and adding bleach every day.

Pool store employees only know what they have been told by previous employees (or chemical companies) ... and apparently they have been passing down bad information for decades. 99% of the pool industry does not seem to understand the CYA/FC relationship ... or they ignore it so they can sell more stuff.

If clean is 10psi, then definitely backwash by 13psi at the most.

 

[linen]

Can't wait to get my test kit.

You will be dangerous with it Which kit are you getting? Many of use have the tf-100 since it is the best value.

I'm gonna be gone this weekend. How often do you test and adjust when not using tabs.

When this stuff is new to you, test everyday until you get the "rhythm" of your pool. For this weekend, I would just raise the pool up towards your SLAM (shock) level.

I was just at pool store seeing what they had. They just won't budge on 150 stabilizer is okay. H
That's there action limit. And when I told them that means more chlorine hey said no it doesn't. What data are they looking at ?

I doubt they are looking at any data, just old antiquated pool care methods.

As for my clean pressure for filter asked above. 10 psig. I've back washed at 13 psig.

That will work.

 

[mishawver]

I bought the TF-100 kit. I already had bought a kit from Leslies that repeats some of the TF-100. It lacked a good chlorine test. I think the CyA and TA tests were good though. However, wanted to go ahead and buy the complete set with TF-100. I'm gonna order the whale brush. Pool maintenance will be so much fun!

 

[mishawver]

I have my test kit and took a my first sample this morning. Here are the results

Free Cl : 8.5 ppm
Total Cl: 8.5 ppm
CyA: 55 - 70 ppm (depends on what is considered not visible for black dot)
pH: 7.5
Hardness: 420 ppm
TA: 60 ppm (not corrected - should I correct for CyA)

I took stabilized tablets out of pool Thursday night and added bleach to boost to bring the chlorine up while I was gone over weekend. I checked before leaving at it was over 10 ppm. When I came back Sunday evening, it was around 3 ppm according to strips.

I do know what crystal clear means now. The water was beautiful. I could see the screws on the drain as mentioned above. When pump is off and water settled, it looked as if pool was empty it was so clear. However the piles of algae settled to the bottom was ugly, but I did vacuum that to waste. I added another gallon of bleach last night and results of that shown above.

Even with the crystal clear pool, looks can be deceiving. I ran brush along bottom and sides, the green film was there. So I assume I will need to do the SLAM process because with a balanced pool and correct upkeep, I should never have to see a green film come off sides when I run brush...is that correct.

A few followup questions based on testing:

Suggestions on reading the CyA tube. For example, when I reached the 70 ppm mark, I "think" I could still see the outline of the black dot. I was holding waist high and standing in sunlight. Not until I got to around 55 ppm did I feel it was completely gone. Since my original test from first post, I have vacuumed twice and refilled, so would expect some dilution.

When I start the SLAM process, is it best to start at night?

Since my water is clear and I have no CCs, would I expect the SLAM process to be completed quickly and be relying on the OCLT to tell me when complete?

After what I've learned here, I'm not sure if I can swim in public pool again.

Thanks for help.